Selectively Trimming Cermet Resistors Down
Original Publication Date: 1979-Oct-01
Included in the Prior Art Database: 2005-Feb-20
Sometimes it is desirable after laser trimming of a cermet module to have a few of the resistors lower in ohmage values. Chemicals, especially H(2)SO(4), KOH and the permanganate etch, usually bring cermet resistor values up. An exception to this is the immersion of the cermet part in a solution of SnCl(2) followed by immersion in a solution of PdCl(2) or by immersion in electroless Cu, both of which greatly affect the Sn/Pb metallurgy.